Baltanas, Spain - Lance Armstrong fell during the first stage of the Vuelta of Castilla and Leon cycling race on Monday and has been taken to hospital.

Some 20 kilometres before the stage finish at Baltanas, Armstrong was involved in a multiple fall and sat on the ground for several minutes, visibly suffering pain to his right arm.

An ambulance later took the 37-year-old American to the Rio Carrion hospital in the nearby town of Palencia.

This was the first race in which the US cyclist was set to compete with the Spaniard Alberto Contador. Both are in the same team, Astana, and are fighting for team leadership.

The seven-time Tour de France champion Armstrong came out of retirement this season. He has already raced in the Tour Down Under, the Tour of California and the classic Milan-San Remo, and he is planning to compete in the Giro d'Italia in May.